The present invention relates to the management of the braking of a motor vehicle fitted with a power-assisted parking brake (usually known under the abbreviation FPA).
This type of automatically power-assisted parking brake constitutes a significant advance over the conventional handbrakes of motor vehicles. Specifically, it becomes possible to apply the rear brakes when the vehicle stops in optimal conditions without the application being too great or too little. It becomes possible to automatically release the application of the parking brake when the driver wants to drive the vehicle forward, for example when the driver engages a gear ratio and accelerates sufficiently to set the vehicle in motion. The application of the parking brake can also be carried out manually via a control, that can be actuated by the driver, on the dashboard of the vehicle. In any case, the automatic release of the parking brake constitutes a hill start assistance. The braking management system can actually, in this case, release the application when the engine provides enough torque to move the vehicle forward depending on the slope determined by a sensor and taken into account by the vehicle's onboard computer.
Such power-assisted parking brake systems comprise many safety functions. It will be possible to refer in particular to French patent application 2 906 515 belonging to the applicant in which automatic application of the parking brake is provided in the event of a malfunction of alarm means signaling an absence of application.
In general, the parking brake is applied with a determined force of application which corresponds to the maximum possible application, which has the drawback of not taking account of the conditions of use of the vehicle and may cause, in the long term, excessive wear reducing the service life of the system.
It can be envisaged not to proceed initially with a maximum application, being content with a provisional application depending on the conditions of use of the vehicle. The force of application can then, in particular, take account of the slope on which the vehicle stands. It is also possible to carry out an application that is less than the maximum application when the engine continues to run although the vehicle is stationary, which means that the driver envisages a temporary standstill. In these various situations, however, it is necessary to carry out a reapplication of the parking brake if a loss of application force is noticed over time, or if the conditions of use of the vehicle change. This however requires the use of additional sensors such as application-force sensors, and leads to a monitoring requirement over time which can be a disadvantage particularly in terms of power consumption.